building back housing in post-disaster situations

Comentarios

Transcripción

building back housing in post-disaster situations

BUILDING BACK HOUSING
IN POST-DISASTER
SITUATIONS – BASIC
ENGINEERING PRINCIPLES
FOR DEVELOPMENT
PROFESSIONALS:
A PRIMER
January 2012
This report was produced for review by the United States Agency for International Development (USAID). It was
prepared by Build Change for International Resources Group (IRG).
BUILDING BACK HOUSING IN
POST-DISASTER SITUATIONS –
BASIC ENGINEERING PRINCIPLES
FOR DEVELOPMENT
PROFESSIONALS: A PRIMER
January 2012
Disclaimer
The authors’ views expressed in this publication do not necessarily reflect the views of the United States
Agency for International Development or the United States Government.
TABLE OF CONTENTS
ACRONYMS ·································································································· V
EXECUTIVE SUMMARY ················································································ VII
OVERVIEW ··································································································· 1
PRINCIPLES AND STRATEGIES ................................................................................... 1
OPTIONS FOR POST-DISASTER HOUSING ................................................................. 2
ADVANTAGES OF HOMEOWNER-DRIVEN RECONSTRUCTION ................................ 5
DRAWBACKS TO HOMEOWNER-DRIVEN RECONSTRUCTION ................................. 6
COST ............................................................................................................................ 7
SUCCESSFUL HOMEOWNER-DRIVEN RECONSTRUCTION ...................................... 8
1.
IMPLEMENTING PARTNERS AND STAKEHOLDERS ·······························11
THE STAKEHOLDERS IN POST-DISASTER HOUSING RECONSTRUCTION ............ 12
2.
PRE-DESIGN ACTIVITIES ·····································································14
2.1.
3.
3.
4.
PRE-DESIGN STEPS......................................................................................... 14
DESIGN······························································································19
2.2.
DESIGN CRITERIA ............................................................................................ 21
2.3.
STRUCTURAL ENGINEERING ANALYSIS FOR TYPICAL FLOOR
PLANS ............................................................................................................... 24
2.4.
DESIGN RULES AND STANDARD DOCUMENTS ............................................ 24
HOMEOWNER-DRIVEN DESIGN ····························································26
3.1.
HOMEOWNER QUALIFICATION ....................................................................... 26
3.2.
HOMEOWNER PREFERENCES SURVEY ........................................................ 27
3.3.
PLOT SURVEY AND SKETCH........................................................................... 28
3.4.
DESIGN AND COST ESTIMATION .................................................................... 28
3.5.
HOMEOWNER TRAINING ................................................................................. 29
3.6.
REVIEW AND PAPERWORK FLOW .................................................................. 29
CONTRACTOR/BUILDER SELECTION ···················································31
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
III
5.
4.1.
BUILDER or CONTRACTOR IDENTIFICATION ................................................. 31
4.2.
CONSTRUCTION CONTRACT .......................................................................... 32
4.3.
PRE-CONSTRUCTION TRAINING or CERTIFICATION .................................... 32
4.4.
PROJECT SCHEDULE ...................................................................................... 33
CONSTRUCTION SUPERVISION ···························································34
5.1.
6.
CONSTRUCTION CHECKLIST .......................................................................... 34
FUND DISTRIBUTION ··········································································36
6.1.
FUND DISTRIBUTION OPTIONS....................................................................... 36
6.2.
FUND DISTRIBUTION SCHEDULE ................................................................... 37
APPENDIX 1: UNDERSTANDING CAUSES OF COLLAPSE CONFINED
MASONRY HOUSES IN INDONESIA·······················································39
APPENDIX 2: HOUSING SUBSECTOR STUDY AND DESIGN CONFINED
MASONRY HOUSES IN INDONESIA·······················································49
IV
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
ACRONYMS
A&E
Architecture and Engineering
CBOs
Community-Based Organizations
EERI
Earthquake Engineering Research Institute
EMMA
Emergency Market Mapping and Analysis
FIDIC
Fédération Internationale des Ingénieurs-Conseils (International Federation of
Consulting Engineers)
GSHAP
Global Seismic Hazard Assessment Program
NEHRP
National Earthquake Hazards Reduction Program
NGOs
Non-governmental organizations
USAID
US Agency for International Development
V
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
EXECUTIVE SUMMARY
This Primer covers the basic steps in the process of selecting a model
for planning and executing post-disaster housing reconstruction projects
funded by the US Agency for International Development (USAID). It is
intended to provide USAID officers and Host Country officials with the
steps, principles, and best practices that need to be taken to properly
carry out housing construction and reconstruction in a post-disaster
situation. It provides a road map on how to develop a project through
planning, design, and implementation and builds on an earlier report,
“Basic Engineering and Construction Management: A Primer.”
The Primer addresses various phases of the planning, design, and
implementation process and the various deliverables and milestones
usually included as part of the process. The document also discusses the
role and responsibilities of the USAID project manager, including
interactions with the affected community(ies), partners, local officials,
and other involved organizations.
The Primer addresses several objectives:
 To greatly reduce deaths, injuries, and economic losses caused by
housing collapses due to natural disasters in developing countries
 Permanently changing building code enforcement or construction
practices so that houses built in the absence of external funding and
technical support are substantively more resistant to collapse during
and after disaster situations
 Capacity building through training of builders, homeowners,
engineers, and government officials
 Permanent change in construction practices by building local skills
and stimulating local demand
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
VII
OVERVIEW
This Primer introduces engineering and development professionals to
the basic steps in the process of selecting a model for planning and
executing post-disaster homeowner-driven housing reconstruction
projects funded by the US Agency for International Development
(USAID). It is intended to provide USAID officers and Host Country
officials with the steps, principles, and best practices that need to be
taken to properly carry out homeowner-driven housing construction and
reconstruction in a post-disaster situation. It provides a road map on
how to develop a project through planning, design and implementation
and builds on an earlier report, “Basic Engineering and Construction
Management: A Primer.”
PRINCIPLES AND STRATEGIES
Post-disaster housing reconstruction presents an opportunity to not only
rebuild safe housing for the affected population, but also to change
construction practice permanently so that local builders, engineers, and
homeowners build safe houses in the future. These objectives are
addressed here by applying the following principles and strategies, which
are documented in the text:
 Local Solutions – Use detailed housing subsector studies to
determine the most cost-effective ways of building disaster-resistant
houses using materials and skills that are available through the local
private sector.
 Technical Excellence – Leverage the knowledge and skills of the
best engineers and architects in the world – both in the US and the
developing world – to ensure that the very best designs and design
thinking are applied to the reconstruction efforts while sticking to a
carefully compiled list of criteria for local sustainability and
acceptance.
 Equality – Empower the homeowners to choose their own layout
and materials and manage their own construction with technical
assistance, by providing a range of solutions appropriate for different
income levels, family size, cultures, and climates.
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
1
 Local Capacity – Build local capacity by hiring and working with
local engineers, architects, builders, universities and governments and
training vocational or trade school students.
 Job Creation – Work with local masons, carpenters, and
homeowners to incorporate disaster-resistant building techniques that
are culturally accepted and easy to adopt with limited training and
education.
 Economic Growth – Kickstart the local economy by purchasing
locally available materials and products.
 Bridging the Gap – Learn and spread best practices from postdisaster housing reconstruction programs so that the many other
agencies involved in these efforts build better houses and leave in
place more sustainable local impacts.
A project’s success over the longer term requires knowledge, skills, and
abilities on the part of those implementing and managing it. However,
many professionals in the developing world have not yet internalized the
core competencies that those in more advanced economies take for
granted. For this reason, USAID incorporates capacity building activities
into many of its engineering projects. This is an integral part of
homeowner-driven reconstruction.
OPTIONS FOR POST-DISASTER HOUSING
The focus of this Primer is on homeowner-driven housing
reconstruction and retrofitting.
Homeowner-Driven Reconstruction. Homeowner-driven
reconstruction is a post-disaster housing reconstruction model that is
gaining in usage and popularity worldwide. It has been successfully
implemented after recent earthquakes in India, Indonesia, China, and
Haiti. More specifically, homeowner-driven reconstruction was the
reconstruction model of choice by government agencies overseeing the
reconstructions following the 2001 Gujarat, India earthquake, 2007 and
2009 West Sumatra, Indonesia earthquakes and the 2008 Sichuan, China
earthquake.1 It can be a lower cost, higher impact model than donordriven reconstruction and can produce safe homes, satisfied
homeowners, and sustainable change in construction practice.
1
2
Though the government of Haiti has not yet released a housing reconstruction policy, homeowner-driven approaches are being
promoted and used by many agencies.
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
Homeowners are empowered to make their own choice, which results in
greater satisfaction and buy-in, an increased willingness to invest more in
earthquake and hurricane safety, and a reduction in dependency.
Homeowners drive the process themselves; they choose the structural
type, materials, layout, and architecture. They usually do not build the
house themselves, but rather hire small scale, local contractors to do the
construction. Financing is provided directly to the homeowner or to
small groups of homeowners in the form of cash grants and/or
materials vouchers.
This approach is most effective when government provides some
enforcement, and/or the provision of grant or loan financing is
contingent upon meeting minimum standards for good construction
quality. In other words, financing should be provided in installments,
with checks on construction quality.
Community-Driven Reconstruction. Community-driven
reconstruction has also been used in recent earthquakes around the world.
It differs from homeowner-driven reconstruction in that homeowners
typically choose from a small number of floor plans and structural systems,
or the choice of structural floor plans is made by a group of community
leaders on behalf of all homeowners. Also, homeowners may not control
the funding, and contractors or small groups of community labor may be
used to build the house.
Donor-Driven Reconstruction Also referred to as contractor-driven
reconstruction, in this model, homeowners are minimally involved in design
or construction, if at all. Houses are designed by the donor or its consultant
and built by a contractor hired by the donor.
The implementation models are described in more detail in the
table below.
Table 1. Comparison of Homeowner-Driven, Community-Driven and Donor-Driven Housing Reconstruction
Implementation Models
Homeowner-Driven
ARCHITECTURE and DESIGN
Who Chooses
Homeowner
Structural System
Who Chooses Floor Homeowner can choose
Plan
any layout provided it
confirms with disasterresistant design standards
Homeowner
High
Satisfaction with
Type and Floor Plan
CONSTRUCTION
Who Builds
Small scale, local builders
hired by homeowner or
small groups of
Community-Driven
Donor-Driven
Donor or government
Donor or government
Donor, community groups or
homeowners choose from a
limited number of floor plans
Donor, or homeowners choose
from a limited number of floor
plans
Can be low if floor plan is
too small, not appropriate
for lifestyle or climate
Can be low if floor plan is too
small, not appropriate for
lifestyle or climate
Local builders or contractors
hired by groups of
homeowners; in limited
Large scale contractors hired
by relief agencies or
governments, may not be local
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
3
Homeowner-Driven
homeowners; in limited
cases, homeowners
themselves
Lowest
Community-Driven
cases, homeowners
themselves
Donor-Driven
Resource
Consumption
Use of Recycled
Highest
Materials
QUALITY AND TIME
Who Supervises
Homeowner, technical
consultant, and/or
government
Quality
Varies; can be high and can
be very poor; depends on
homeowner’s budget and
desire for a safe house;
helps if government
enforces building standards
High
Highest
Low
Rare
Homeowner, community
group, technical consultant,
and/or government
Varies; can be high and can
be very poor; depends on
competence of
implementing agencies and
willingness to enforce
quality standards
Contractor, technical
consultant, and/or government
Homeowner
Confidence in
Construction Quality
Potential for
Corruption
Can be highest (if funding
sufficient)
Varies
Low; “owner” is the
homeowner
Highest; “owner” is donor or
contractor
Speed
Unpredictable, can be
accelerated through fast,
sufficient disbursement of
cash grants
Genuine but not always
finished or pretty
Medium; “owner” is the
implementing agency or
donor, more peer pressure
mechanisms in place
Can be fast or slow
Varies
Good
Homeowner, with grant from
government or donor, their
own savings and/or loan (if
available)
Donors or government pay
community groups or
contractors directly
Who Hires Builder
Homeowner
Who Buys Materials
Homeowner or Builder
Level of
Homeowner
Contribution
Who Profits
Highest
Community Group or
Implementing Agency
Community Group,
Implementing Agency, or
Contractor
Medium
Implementing agencies or
government act as contractors
or hire and pay contractors,
contractors purchase materials
and hire labor
Donor or Implementing Agency
Photo Op
FINANCIAL
Who Pays
Local builders and materials
producers
COST PER HOUSE
Design
High
Construction
Low
Management
Materials and Labor Lowest
On-the-job training
Highest
Overall Cost to
Lowest
Donor
DEVELOPMENT POTENTIAL
Type of Model
Bottom-up
Role of
4
Limited to technical
Varies; can be high and can be
very poor; depends on
competence of implementing
agencies or government staff,
avoiding corruption, and
willingness to enforce quality
standards
Can be low (homeowner not
involved)
Fast if managed well, slow if
not
Donor, Implementing Agency,
or Contractor
Lowest
Community members, local
builders and materials
producers
Contractors, consultants,
larger-scale materials
producers, maybe non-local
Low
Depends
Low
High
High
Depends
Varies
Highest
Low
Highest
Top-down with some
bottom-up elements
Limited to technical
Top-down
More extensive; design-build,
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
Implementing
Agencies
Donor Contribution
Potential to Cause
Long-Term Change
in Practice
Potential to
Increase
Dependency and
Cause Social
Conflict
Where Model Has
Been Used For
Permanent Housing
Host Country
Government
Preference
Homeowner
Satisfaction
Homeowner-Driven
assistance only; may
provide materials vouchers
or cash grants to
supplement government
grants
Technical assistance,
capacity building, cash to
build a house
Highest
Community-Driven
assistance, grant
disbursement
Donor-Driven
hire contractors, manage
construction
Varies, technical assistance,
capacity building, cash,
house
Depends
House
Lowest; empowers
homeowners to drive
process, allows for more
equitable treatment
Depends
2001 Gujarat, India; 2007
and 2009 West Sumatra,
Indonesia; 2008 Wenchuan,
China; 2010 Haiti; and
others
Preferred model in India,
Indonesia, China. Indonesia
now strongly discourages
donor-driven housing.
2004 Aceh, Indonesia; 2004
Sri Lanka; 2005 Balakut,
Pakistan; 2006 Central
Java, Indonesia; and others
Highest; houses are given
away, homeowners are not
empowered; due to high cost,
unlikely all will be treated
equitably
1993 Maharashtra, India; 2001
Gujarat, India; 2004 Aceh,
Indonesia; and others
Highest, except for
homeowners with the most
limited funds
Varies; model can result in
conflicts between
homeowners and
communities if quality or
size of house varies by
agency
Varies
Low
High initially due to apparent
scale, efficiency, and possibility
for kickbacks in some
countries; lower as costs rise
and social conflicts occur.
Varies; model can result in
conflicts between homeowners
and communities if quality or
size of house varies by agency
ADVANTAGES OF HOMEOWNER-DRIVEN
RECONSTRUCTION
Working directly with homeowners to choose the design and hire and
oversee builders is a rewarding process that can result in safer houses
and satisfied families. Empowering homeowners, builders, construction
professionals, and local governments to drive change is a more costeffective and lasting solution than building houses for people. But these
households will not build an earthquake-resistant house unless they can
afford to and they need access to technology, materials, and skilled
construction professionals. They also need incentives and government
ministries able to enforce the building standards. By addressing all three
barriers – technology, money, and people – the homeowner-driven
development model encourages the growth of an environment in which
earthquake-resistant construction becomes the common practice.
Homeowner-driven reconstruction can:
Increase Safety
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
5
 Provide a more complete, structurally integrated solution than a core
home or partially built home.
 Result in a disaster-resistant building, if sufficient financing and
incentives for following standards are provided.
 Increase the technical capacity of the workforce, including engineers,
site supervisors, builders, materials producers, and other construction
professionals, if coupled with technical assistance.
Increase Homeowner Satisfaction
 Produce a more satisfied, empowered homeowner.
Increase Sustainability.
 Leverage the financial resources of the homeowner. In homeownerdriven reconstruction, homeowners can add in their own financial
resources, resulting in a larger and more long-term solution.
 Reuse or recycle materials, reducing the overall cost per house.
 Put resources back into the local economy. Homeowners typically buy
local materials and hire local labor.
 Stimulate investment in local businesses, which creates jobs.
 Stretch the donor’s dollar further by reducing the donor contribution
per house.
DRAWBACKS TO HOMEOWNER-DRIVEN
RECONSTRUCTION
Homeowner-driven reconstruction may:
 Take longer. When the homeowner is driving the process, it is
difficult to control the pace of the reconstruction. Thus, homeownerdriven reconstruction requires a patient donor.
 Result in some unfinished houses. If the financial subsidy and
homeowner’s funds are not sufficient to complete the house, the
homeowner may not finish it during the grant period.
 Result in some houses that are not disaster-resistant. If the financial
subsidy and the homeowner’s funds are not sufficient to complete the
house in a manner which is disaster-resistant, the homeowner and
builder may not produce an disaster-resistant house. In addition,
corruption or lack of will may reduce construction quality.
6
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
 Produce houses that are less attractive for photographs. Homeowners
may not choose to finish the house during the course of the grant –
they may not plaster or paint the house until further funding is
available. Thus, it is difficult to obtain picture-perfect images of
houses for reports and PR materials.
Homeowner-driven reconstruction may not be the best choice for largescale greenfield, relocation, or multi-unit commercial developments,
which may be more efficiently designed by Architecture and
Engineering (A&E) firms and built by large-scale developers or
contractors. However, implementers of such projects should consider
including elements of homeowner-driven reconstruction in these
projects, such as enabling the homeowners to choose the structure type
and layout, training of local construction professionals, and the universal
need to supervise and oversee construction to ensure quality.
COST
The following describes the cost of homeowner-driven reconstruction
as compared to alternative approaches for reconstruction programs, by
contrasting the reconstruction programs in Aceh and West Sumatra,
Indonesia. Findings may be different elsewhere.
Cost of House: The overall cost of the house materials and labor and
the donor cost per house can be lower in homeowner-driven
reconstruction than donor-driven reconstruction. Consider the
following two cases:
 After the 2004 Indian Ocean tsunami hit Aceh, Indonesia, donor and
community-driven approaches were used. Cost of house materials and
labor including donor/NGO direct and indirect costs were on the
order of US$12,000 – US$20,000 for a 36m2 house. This does not
include additional costs incurred by some agencies to retrofit or tear
down and rebuild newly built houses which were built to inferior
quality standards.
 After the 2007 and 2009 earthquakes in West Sumatra, Indonesia,
homeowner-driven approaches were mandated by the Indonesian
government; the government provided $1,700 in cash support to
homeowners who lost houses. Technical assistance was provided by
local universities, government subcontractors and foreign technical
assistance providers. Cost of house materials and labor including
technical assistance was on the order of US$3,000 – US$8,000.
Reasons for this cost differential:
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
7
 Donor/Implementing Agency Costs: In a donor-driven model, the
donor typically has high direct and indirect costs – vehicles, staff,
warehouses, procurement infrastructure, expat salaries, project
management, etc. In a homeowner-driven model, though foreign
agencies may be involved in providing technical assistance, costs will
be limited to personnel, which can be low if local engineers and
construction professionals are relied upon.
 Price Escalation: Though donors/non-governmental organizations
(NGOs)/contractors can sometimes get lower prices because they can
buy in bulk, usually in a post-disaster situation in which substantial
foreign aid funding is available, unit prices will go up due to the
demand and the perceived deep pockets of the foreign aid agencies.
These agencies were not present in West Sumatra, demand was lower
and spread out over a longer timeframe, thus fluctuations in prices
were more likely associated with normal market changes.
 Reduced Theft And Corruption: Homeowners are more likely to
protect and avoid theft of materials they purchase themselves.
 Reusing Materials: In a donor-driven model, all materials are usually
purchased new. In homeowner-driven, the homeowner usually uses
some salvaged or stockpiled materials, such as old window and door
frames, timber, roof sheets, sometimes bricks. This reduces the cost
of the building.
 Finishing: Donors may provide a completely finished house –
plastered and painted. Homeowners may wait to paint their house
until they can afford it.
 Choice of a More Affordable Structure: In Aceh, homeowners and
donors chose more expensive and difficult to build structural systems
(confined masonry and reinforced concrete frame with masonry infill)
because they could, donors would pay for it; and the environment was
such that competition existed between aid agencies. In West Sumatra,
an increasing number of homeowners choose to build from timber
frame with a masonry skirt wall – a less expensive, easier to build,
more earthquake-resistant building.
SUCCESSFUL HOMEOWNER-DRIVEN
RECONSTRUCTION
The homeowner-driven reconstruction model is most effective when the
essential technical, financial and social components are in place.
8
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
Technical: Earthquake-resistant construction will become common
only if the right technology is locally available, widely known, and
culturally accepted.
 Technology Choice: It is easier and more effective to make
improvements to existing building methods, rather than introduce
something new. When given the choice, homeowners will choose
what they are already familiar with. The opportunity exists to work
with the homeowner to build better using locally available materials
and techniques.
 Standards: A clear, complete, consensus-based, government produced
or endorsed guideline for each common structural system that
consists of design rules and component drawings, and can be applied
to any floor plan.
 Capacity: Trained builders, engineers, architects, building materials
suppliers.
Financial: Homeowners must have access to sufficient funds to rebuild
safely and completely.
 Access to Capital: Sufficient funding in the form of grants, loans, or
materials vouchers.
 Incentives: Provision of financing must be contingent on applying
minimum standards.
 Subsidies: Subsidies or price controls on certain building materials.
Social: Someone has to want the house to be earthquake-resistant.
 Motivation: Demand creation among homeowners, tying financing to
compliance with building standards.
 Enforcement: Building standard enforcement by government officials,
donors, or a third party.
The following table contrasts homeowner-driven reconstruction
programs in three countries in terms of the above criteria.
Table 2. Comparison of Homeowner-Driven Housing Reconstruction Programs in India, Indonesia, and China
2001 Gujarat, India
2007 and 2009 West
Sumatra, Indonesia
2008 Wenchuan, China
Wide Ranging and Flexible –
Government provided
prescriptive reinforcement
details but allowed many types
Sufficient – Government
allowed two most common
structural systems – timber
frame with masonry skirt and
Sufficient – Government allowed
the most common structural
system – confined masonry with a
reinforced concrete roof – but
TECHNICAL
Technology Choice
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
9
2001 Gujarat, India
of wall materials (brick, block,
stone); also allowed earthbased systems
2007 and 2009 West
Sumatra, Indonesia
confined masonry – but initially
discouraged the former
2008 Wenchuan, China
discouraged timber roof with clay
tiles
Standards
Clear and Comprehensive –
prescriptive standards issued
by government, except for
gable wall reinforcement
Limited – a variety of
standards and guidelines
available, but not clear and
comprehensive standard
issued by government
Limited – a variety of standards
and codes available from national
to local, but applying to typical
houses required judgment and
interpretation
Capacity
Sufficient; capacity building
programs were implemented
Limited capacity building by
universities and technical
consultants
Sufficient capacity, limited
capacity building needed
Access to Capital
Sufficient cash grant provided
by government to most
homeowners
Insufficient cash grant
provided by government,
limited donor agency funding
following 2009 earthquake
Sufficient cash grant and loan
access provided by government to
most homeonwers
Incentives
Yes – funding given out in
installments,
No – limited to no building
standard enforcement by
government
Varies – incentives given to
builders
Subsidies
Some
None
Some
Homeowner
Motivation
High – funding contingent
upon meeting standards
Homeowner, community
group, technical consultant,
and/or government
Contractor, technical consultant,
and/or government
Building Standard
Enforcement
High – government employed
a third party quality inspector
None
Varied – depended on contractor,
government and presence of
external technical consultant
Completion Rate
High completion rate
Mixed; higher completion rate
for timber frame houses than
confined masonry houses
High completion rate
Building Standard
Compliance Rate
High compliance rate except
for gable wall reinforcement or
cases in which third party
inspector was absent, or not
competent
Mixed: higher standard
compliance rate for timber
frame houses; lower for
confined masonry
Varied; higher in areas with
external technical consultant
FINANCIAL
SOCIAL
OVERALL SUCCESS
10
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
1. IMPLEMENTING PARTNERS
AND STAKEHOLDERS
Key roles must be filled in order to execute a homeowner-driven
housing reconstruction program: technical consultant(s) for design and
construction supervision, and implementing partner(s) for homeowner
selection and fund distribution.
It is possible and recommended that the same organization be used as
the technical consultant for design and construction. The technical
consultant or consultant team could be an A&E firm, a specialized nonprofit organization or social enterprise, a team of local experts from the
academic and business sector, or any combination of the above.
However, the implementing partners for design and construction should
be different from the implementing partner for homeowner selection
and fund distribution. Separating these roles preserves the consultant
relationship between the homeowner and technical consultant; the
technical consultant is seen as a trusted advisor rather than a source of
funding, which facilitates a better dialogue about safe construction. Plus,
this separation better mirrors the contracting requirements and
separation of roles under FIDIC (Fédération Internationale des
Ingénieurs-Conseils or International Federation of Consulting
Engineers).
Additional partners may be needed for other activities which are
necessary prior to housing reconstruction but are outside the scope of
this Primer. Those activities include but are not limited to the following:
 Rubble clearing
 Property rights and land titles
 Community mapping and planning, with plot boundaries identified
 Infrastructure planning and implementation
Options for selection of and contracting with the technical consultants
and implementing partners are covered in other resources.
BASIC ENGINEERING AND CONSTRUCTION MANAGEMENT STUDIES
11
THE STAKEHOLDERS IN POST-DISASTER
HOUSING RECONSTRUCTION
There are a number of stakeholders involved in post-earthquake housing
reconstruction. It is important to clearly define the role of each
stakeholder group and leverage their core competency. The major
stakeholder groups and their roles are identified in this section.
Donor, in this case, USAID:
 Provide funding for the technical assistance and other work
 Manage disbursement of financial subsidy to homeowner or
community group for materials and labor, or oversee the distribution
of funding by an implementing partner
Government (Relevant ministries, municipal engineers, and building
inspectors):
 Produce consensus-based, clear, easy-to-implement building standards
and guidelines
 Provide certification programs for builders, engineers, government
officials
 Provide building inspections, drawing reviews, and quality supervision
 Manage disbursement of financial subsidy to homeowner or
community group
Homeowners:
 Select the type of structure, layout, materials, and architecture
 Procure the building materials
 Hire the contractor
 Oversee construction
 Pay for building materials and pay the contractor
Community Groups:
 Select homeowners who qualify for the program
 Assist with gathering homeowners for informational meetings and
resolving disputes
 Assist in resolution of land rights and property boundary issues
12
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
 Identify local builders, building materials suppliers, and other
stakeholders
Technical Assistance Providers (Engineers and architects who
provide support in developing the building standards and direct
technical assistance to homeowners during reconstruction):
 Develop design, construction, siting and materials guidelines, related
resources and tools in support of the government and in partnership
with all stakeholders
 Provide training and capacity building to homeowners, builders,
engineers, and government officials
 Guide the homeowner through the design, builder selection, and
construction process
 Supervise construction and provide hands-on training to builders as
needed
NGOs/Community-Based Organizations (CBOs): work with
community groups and homeowners to:
 Clear debris
 Resolve land tenure issues
 Implement infrastructure projects
 Do civil works such as building retaining walls that apply to more
than one house
 Manage disbursement of financial subsidy to homeowner or
community group.
US Agency for International Development
USAID is usually the sponsor of the housing project, and in the case of
homeowner-driven housing reconstruction, it contracts directly with
engineering and construction companies as technical assistance
providers and implementing partners to distribute funds to homeowners.
BASIC ENGINEERING AND CONSTRUCTION MANAGEMENT STUDIES
13
2. PRE-DESIGN ACTIVITIES
In the wake of a disaster, several activities must take place before
reconstruction or retrofitting of permanent housing can begin.
In addition, certain actions, such as conducting an environmental
analysis, are required for any USAID project. These mandatory
requirements are described in the report “Basic Engineering and
Construction Management: A
1
Assess safety and tag affected
Primer.”
buildings
2.1. PRE-DESIGN STEPS
Post-disaster housing
reconstruction projects require
several sets of activities before the
project can enter the design phase.
2.1.1. ASSESS SAFETY
AND TAG BUILDINGS
2
Use post-earthquake
reconnaissance and forensic
engineering to understand
causes of collapse
3
Assess other hazards
4
Do housing subsector and
market studies
5
Determine which building
standards apply
6
Evaluate location options
7
Clarify objectives, performance
criteria
Rapid safety assessments will allow
for a quick inventory of damaged buildings, and facilitate the quick
return of some homeowners to undamaged, safe buildings. An ATC-20
2
type survey was used successfully following the January 12, 2010
earthquake in Haiti.
2.1.2. UNDERSTAND CAUSES OF COLLAPSE
A post-earthquake environment presents an ideal laboratory in which to
learn why buildings collapsed and why they do not. Forensic engineering
studies are regularly performed by professional engineers, technical
assistance providers, and research institutes such as the Earthquake
Engineering Research Institute (EERI) to document lessons learned and
make recommendations for safe rebuilding. Identifying causes of
collapse can help shape and inform reconstruction guidelines, especially
in situations in which building codes or guidelines are not available.
2
ATC-20 is a rapid method for evaluating the safety of buildings after earthquakes, developed by the Applied Technology Council.
Implementation results in placarding or tagging buildings as follows: INSPECTED (apparently safe, green placard), LIMITED
ENTRY (yellow placard), or UNSAFE (red placard). More information is available at https://www.atcouncil.org/downloads/atc-20download.html
14
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
See Appendix 1 for a summary of causes of collapse for confined
masonry buildings in Indonesia.
2.1.3. ASSESS OTHER HAZARDS
Additional studies may be needed to quantify the likelihood and
magnitude of future disasters, including the following:
 Earthquakes
 Tsunamis
 Hurricanes, cyclones or high winds
 Floods
 Landslides
 Climate extremes
2.1.4. DO HOUSING SUBSECTOR STUDIES
It is easier and more sustainable to make minor low or no-cost
improvements to existing ways of building, than it is to introduce a
completely new technology or reintroduce a traditional building method
that is no longer common. Housing subsector studies address the
following questions:
 What types of houses do people want to build here, now? For
example, will people build from timber, masonry, earth, or some other
structural system?
 What size, shape, number of stories and layout are common?
 Where do people cook? Bathe? Use the toilet?
 What are the common architectural, cultural, and climate preferences?
Have these preferences changed as a result of the disaster?
 What materials are used, where are they produced, how much do they
cost, will the production be able to meet demand? Who buys the
materials (homeowners, builders, contractors)?
 What is the skill level of local builders? What tools and techniques do
they use? How much do they earn?
 How are houses commonly built – Do homeowners build themselves
or hire local builders? Or are housing units built by the government or
through the commercial private sector?
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
15
 What other issues may arise during reconstruction – security, conflict?
The most effective way of obtaining the above information is through
direct interviews and surveying of various stakeholder groups, such as
homeowners, builders, building materials producers, and municipal
officials. The Emergency Market Mapping and Analysis (EMMA)
Toolkit3 has become a popular method of rapidly assessing the market
for reconstruction after a disaster.
2.1.5. DETERMINE WHICH BUILDING STANDARDS
APPLY
In the pre-design phase, it is necessary to determine if relevant and
adequate building codes and standards exist in the project country.
Codes may not exist, or the codes may not be relevant to the most
common structural system used for housing. For example, in many
developing countries, building codes for multi-story buildings may exist,
but applying these codes to a single or two-story single family home may
result in overly conservative design and construction guidelines which
lack important details on essential techniques to build an earthquakeresistant structure.
The codes and standards used should meet the standards applicable in
the country in which the project is located. If such standards are not
available, regional or international standards can be used. US standards
are typically used on USAID projects; however, these usually exceed
local codes and standards.
In the case of incomplete or inapplicable building codes, the best design
solution may be a mix of international building codes, existing simple
design and construction guidelines, and engineering judgment to arrive
at a solution that is sufficiently safe yet affordable, sustainable, and
implementable for the local context. Appendix 2 contains a review of
standards for confined masonry homes in Indonesia.
2.1.6. EVALUATE LOCATION OPTIONS
Every effort should be made to facilitate reconstruction of homes in
their original location; however, government-mandated land
reorganization or decentralization or presence of extremely hazardous
site conditions may necessitate the need for relocation. The choice to
relocate displaced individuals to new settlements should not be made
3
http://emma-toolkit.org/
16
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
without serious consideration of the possible consequences, including
but not limited to the following:
 Additional cost of land acquisition
 Additional cost of roads, sewers, utilities, and other infrastructure
 Inability to connect homes to utilities
 Disruption of social network
 Lack of employment opportunities
 Lack of services
 Lack of or additional cost of transportation
 Change in environment and space, such as lack of trees, sources of
shade, and communal spaces
Furthermore, unclear or poorly documented property rights have the
potential to seriously delay post-disaster housing reconstruction
programs. Techniques and case histories for resolving these issues to a
donor’s expectation are beyond the scope of this Primer.
2.1.7. CLARIFY OBJECTIVES AND PERFORMANCE
CRITERIA
At this stage of the studies, the project team, in consultation with project
country government officials, must decide on performance objectives
and priorities. Some questions to be addressed:

Should damaged houses be repaired (returned to pre-disaster
conditions) or retrofitted (strengthened to resist the next
disaster)? To what performance level should houses be rebuilt
or retrofitted? A common performance level for housing is life
safety, which according to National Earthquake Hazards
Reduction Program (NEHRP) means that significant damage to
structural elements may occur, but a margin remains against
collapse. Occupancy may be prevented until repairs can be
implemented.
Some design criteria for consideration are the following:
TECHNOLOGY
 Disaster-resistant in design – compliant with standards and guidelines
 Disaster-resistant in construction – built with quality workmanship
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
17
 Durable and permanent
 Built with locally available materials, skills, and tools
 Easily expanded and maintained using locally available materials and
skills
 Where possible, reuses materials
 Can be built incrementally, improved from transitional to permanent,
and/or expanded horizontally or vertically
MONEY
 Competitive in cost with local, common (but vulnerable) building
methods
PEOPLE
 Environmentally neutral – using no illegal materials
 Suitable to the climate
 Culturally appropriate in architecture, space, and features
 Secure from break-ins and pests
 Designed and built with the participation of the people
 Trusted by the inhabitants who believe their house will survive a
disaster.
18
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
Following are some examples of consequences when a detailed housing subsector study is not
completed and/or design criteria are not followed.
1)
Poor choice of structural system. Following the 1993 Killari Earthquake in eastern Maharashtra,
India, an agency implemented a geodesic dome type building for housing reconstruction. This
design choice certainly meets disaster resistance criteria, however, according to the
homeowners, the structure is not culturally appropriate in architecture, space and features. The
homeowners complained that the interior was too dark, air circulation was poor, and it was not
easy to divide the interior space for privacy. Furthermore, the homeowners could not extend the
house easily, and used poorly confined masonry to do so. Because the agency implemented a
building technology that was not common or culturally appropriate, the opportunity to train local
homeowners and builders in common techniques was missed.
2)
Poor choice of layout. Following the 2001 earthquake near Bhuj in Gujarat, India, though most
homeowners opted for homeowner-driven reconstruction; some homeowners received a house
designed for them by a relief agency. In this case, the agency chose to put the toilet inside the
house, though the common preference for the toilet in this area is outside the house. As a result,
the toilet is unused, space is wasted in a small dwelling, and structural modifications could be
made that reduce the disaster resistance of the building.
3)
Lack of homeowner involvement in reconstruction. Following the 1993 Killari, India earthquake, a
contractor-driven approach was used in which homeowners were minimally involved. Ten years
after the earthquake, these homeowners were still sleeping outside their house because they did
not trust that the concrete was mixed with enough cement to withstand the next earthquake.
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
19
3. DESIGN
The design phase entails the compilation of design criteria, structural
engineering analysis for a few typical floor plans, and development of
prescriptive design rules for application to a variety of configurations.
This phase also includes the preparation of component drawings, bills of
quantity, construction specifications, estimated manpower needs, and a
construction schedule for each structural system likely to be selected by
a homeowner.
The objective of the design phase in a homeowner-driven housing
reconstruction technical assistance program is to develop a set of
prescriptive guidelines that could apply to a variety of floor plans and
horizontal and vertical configurations. The first step is to complete a
detailed structural analysis of a few common floor plans. General design
rules are extrapolated from this process in order to enable homeowner
choice of building materials, layout and other design features while
ensuring the house is sufficiently disaster-resistant.
Design Criteria
Codes and standards
Loading and structural design criteria
Siting and foundation criteria
Architectural criteria
Building materials properties
Structural Analysis
for Typical Floor
Plans
Detailed structural engineering analysis
Detailed structural, architectural, and construction
drawings for typical horizontal and vertical
configurations
Detailed technical specifications
Bill of quantity and cost estimate
Construction schedule
Installment payment schedule
Design Rules and
Standard Documents
Design rules for application to a variety of floor
plans
Component drawings
Quantity and cost estimating form
Cost estimate per unit of floor area
Contract template
The phases of design are as follows
20
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
2.2. DESIGN CRITERIA
2.2.1. CODES AND STANDARDS
The compilation of codes and standards should include local, relevant
codes and guidelines, supplemented with international standards where
needed. The selection should include structural design codes as well as
material design codes. The selection may include relevant simple
guidelines or handbooks from the project country or for similar
structural systems used around the world.
2.2.2. LOADING AND STRUCTURAL DESIGN
CRITERIA
Similarly, load codes and loads for design should be selected based on
local relevant codes and supplemented with international standards. The
following loads should be specified (if relevant):
 Gravity
 Dead
 Live
 Snow
 Flood
 Wind
 Seismic
Seismic loads should be based on seismic hazard mapping. If detailed
studies are not available for the project country, the Global Seismic
Hazard Assessment Program (GSHAP) mapping can be used4.
2.2.3. SITING AND FOUNDATION CRITERIA
Critical factors to consider in evaluating existing and new sites for
reconstruction include soil conditions, slope and slope stability, potential
for settlement and liquefaction, flood risk, and proximity to known
faults. Examining regional, local, and neighboring sites for evidence of
hazardous conditions is helpful when it is unlikely that a formal soil
investigation will be performed for each building site.
4
The Global Seismic Hazard Assessment Program (GSHAP) produced global and seismic hazard maps. Please see
http://www.seismo.ethz.ch/static/GSHAP/
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
21
At a minimum, maximum percent slope should be specified, allowable
soil bearing capacity should be estimated, soil type specified, and during
the analysis, foundation design should be checked for uplift due to wind
and seismic loading.
2.2.4. ARCHITECTURAL DESIGN CRITERIA
Architectural preferences should be gathered from visual inspection of
recently built structures, recent publications on architectural preferences,
and interviews with stakeholders, particularly homeowners. Preferences
will likely vary based on location (urban vs. rural).
Preferences on the following should be collected in the housing
subsector study described previously. Design suggestions and
parameters should be specified on the following:
 Structural System, such as confined masonry, unreinforced masonry,
timber frame with infill, earth-based systems; materials to avoid and
use in construction
 Configuration and Layout, including typical number of stories, layout
and usage of rooms including kitchen and toilet, size of rooms,
presence and design of porch, garage, parapet wall, and other features;
specify maximum room size, special considerations for parapet walls,
overhangs, and open space on the ground floor of multi-story
buildings; consider Sphere project standards
 Floor and Roof Elevations, including floor-to-ceiling heights, specify
finished floor elevations and maximum and minimum floor-to-ceiling
height
 Future Building Additions, evaluate the likelihood of future building
additions for consideration in design; for example, even if a one-story
building is anticipated in the funded reconstruction program, the
single-story building may require design for a second story if that is
likely during the lifetime of the building
 Doors and Windows, including size, materials, typical locations, and
security considerations; specify the preferred location, maximum size,
and reinforcement alternatives in the event the cultural preference is
for a larger than suggested opening; consider requirements for
ventilation and light and positioning to minimize intrusion of rain and
sun
22
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
 Roofs, typical styles and materials for roofs, specify pitch, elevation,
waterproofing and drainage, minimum and maximum eave projection,
and considerations for rainwater harvesting systems
 Stairs, identify typical locations and materials used for stairs, specify
structural and connection details
 Water, Sanitation, and Electrical, determine common placement of
utilities and specify the locations to avoid.
2.2.5. BUILDING MATERIALS PROPERTIES
Typical materials properties should be gathered and minimum materials
strengths should be suggested. Common building materials include the
following:
 Aggregates, such as sand and gravel: specify size, gradation, and
acceptability of using rounded gravel
 Cement and Lime, evaluate the prevalence of lime and cement
products such as Portland Type 1 cement and blended products with
additives, recommend appropriate products for each application, such
as foundation, reinforced concrete, and masonry
 Masonry units, such as fired bricks, concrete blocks, earth blocks,
stone; specify minimum strength and allowable size deviations
 Steel reinforcement, specify size, strength, and acceptability of using
smooth bar and reused steel
 Structural timber, specify grade, treatment
 Structural steel, specify size and grade
 Wall coverings, such as plywood, mineral board, fiber cement board,
chain link fencing, bamboo mats, or other products; specify size,
treatment, and strength
 Roof coverings, such as clay tiles, thatch, corrugated galvanized iron,
corrugated plastic or asbestos sheets; specify size, thickness, and
treatment
 Connectors, such as nails, screws, roof tie downs
 Hardware, such as door knobs and hinges and window latches
 Utilities, such as piping, toilets, faucets, electrical boxes and switches.
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
23
For all cases, specify materials to avoid. Information should also be
provided on:
 Tools and equipment
 Scaffolding and shoring, determine minimum specifications and
availability
 Mechanical equipment, such as mortar and concrete mixers; such
machinery is not often used in the construction of single family
housing in developing countries.
2.3. STRUCTURAL ENGINEERING ANALYSIS
FOR TYPICAL FLOOR PLANS
Once the project management team has completed its review of the
design criteria, the technical consultant should be given permission to
proceed to the structural engineering design phase for one or more
typical floor plans for each structural system.
Deliverables for the structural analysis phase include:
 Structural analysis narrative, which explains the assumptions and
limitations of the analysis
 Structural, architectural, and construction drawings to an acceptable
standard showing in detail the proposed construction
 Technical specifications
 Bill of quantity and cost estimate
 Construction quality checklist
 Construction schedule
 Installment payment schedule
2.4. DESIGN RULES AND STANDARD
DOCUMENTS
Once the project management team has completed its review and
approval of the structural analysis on a few typical floor plans, the
technical consultant should proceed to the development of design rules
and associated documents that can apply to a variety of floor plans.
Deliverables for this phase include:
 Design rules
24
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
 Standard detail drawings
 Simple cost estimating tool
 Simple construction scheduling tool
To see a set of design rules and standard documents for confined
masonry homes for Haiti, please go to:
http://www.buildchange.org/HousingPrimer.html
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
25
3. HOMEOWNER-DRIVEN
DESIGN
This phase of a homeowner-driven housing reconstruction project
extends the design phase to the individual design of each house with the
homeowner.
It should be noted that this phase may result in refinement and revision
of the documents prepared in the previous phase. As such, it is
recommended to use the same technical consultant team for the entire
design phase.
Initially, the project team should introduce the program to community
leaders to gain their endorsement. A community meeting should be held
with all homeowners to explain the process, schedule, requirements, and
their responsibilities for receiving grant funding.
The next step is to interview each homeowner and to inspect their plot
or existing home in the case of retrofitting. It is recommended that local
engineers and architects be employed in this process to minimize
misunderstandings due to language and cultural differences and to
achieve the goal of capacity building and job creation in a post-disaster
environment.
During the initial meeting with the homeowner, a trained architect or
engineer can develop a simple hand sketch of the floor plan for
homeowner review and input. Also, a quick cost estimate can be
obtained using a simple estimating tool in order to allow for
modification of the plan in the event that the homeowner’s aspirations
are beyond their budget.
3.1. HOMEOWNER QUALIFICATION
To qualify for homeowner-driven reconstruction technical and financial
assistance, homeowners should:
 Apply for it. It should be up to the homeowners to decide to
participate in the program. In the initial stages, homeowners should
not need to specify if they are applying for retrofit or new
construction; this is an informed decision to be made by the
homeowner after the retrofit evaluation.
26
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
 Document their rights to land to the expectation of the donor
 Declare that they are building residential unit(s), as opposed to a
commercial property
 Attend a workshop on disaster-resistant design, construction, and
materials standards
 Sign a contract with the donor or implementing partner in which they
agree to meet minimum standards for earthquake and hurricane safety
(or other relevant disaster-resistant standards), and acknowledge that
provision of funding is contingent upon meeting minimum standards
 Review and provide sign-off on the floor plan, structural details, and
bill of quantity
 For new housing, clear the property of debris; for retrofitting, prepare
the building for retrofitting by removing contents and temporarily
relocating if necessary
 Choose builders and building materials suppliers who have been
certified by the government, donor, technical assistance provider or
others
 Protect materials from theft and damage (store cement out of the
rain)
 Assist with supervision of materials and construction quality
 Pay building materials suppliers and builders in a timely and fair
manner.
3.2. HOMEOWNER PREFERENCES SURVEY
The engineer or architect employed by the technical consultant will sit
down with each homeowner and fill out a homeowner preferences
survey. This survey collects much of the same data as in a housing
subsector study, but specific to each homeowner. The homeowner
preferences survey includes the following:
General Data
Homeowner name, address, ID
House address, GPS coordinates
Surveyor name and survey date
Homeowner Data
Family structure, number of family members, gender
Special needs or mobility issues
Current living situation
Land tenure status
Job and income
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
27
Old House Facts
Location, size, layout, materials, earthquake-related
damage, other issues such as ventilation, leaky roof,
security
Location of kitchen and bath, septic and well,
electrical hookups
New House
Preferences
Preferences for size, layout, materials, locations of
windows and doors
Priorities (size, durability, safety, comfort, services
such as kitchen and bath)
Willingness to share walls or live in multi-unit
dwellings
Intention to expand horizontally or vertically
Homeowner
Contribution
Design – Does the homeowner want to choose the
layout, materials, and architectural features?
Construction – Does the homeowner want to build
himself, choose the contractor, supervise
construction, or remain uninvolved?
Materials contribution – Does the homeowner
have stockpiled or salvaged materials for use in
rebuilding? What type and how much?
Construction inputs – Can the homeowner provide
water and/or electricity to be used during
construction?
Funds contribution – Can the homeowner
contribute funds to build a larger or more disasterresistant home?
3.3. PLOT SURVEY AND SKETCH
The architect or engineer should inspect the plot to orient the house on
the plot, note the presence or absence of utilities, drainage, septic
systems, wells, trees, excavations, or other obstacles which may impact
the design and construction of the home or access to the property. The
architect or engineer should pay special attention to the orientation of
the house and sanitation facilities relative to sun, wind, and cultural
norms. A plot sketch should be prepared.
3.4. DESIGN AND COST ESTIMATION
The architect or engineer should then prepare a plan, elevation and
detailed cost estimate for the home. Depending on schedule and budget,
this can be done using hand sketches and calculators, or drafting
software and spreadsheets. Once the design documents are completed,
the architect or engineer should meet again with the homeowner to gain
the homeowner’s approval or make the necessary modifications.
For large-scale projects, common floor plans tend to be used by more
than one homeowner, offering economies of scale.
28
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
3.5. HOMEOWNER TRAINING
Prior to start of construction, groups of homeowners should attend short
training courses on safe construction, in order to empower the
homeowners to assist with construction supervision. When provided with
basic information such as relative proportions of cement, sand, and gravel
required to achieve the specified concrete strength, homeowners can play
an integral and valuable role in construction supervision. Sharing such
knowledge with homeowners can build their confidence that their house
will withstand the next earthquake, and contribute to long-term recovery
from the traumatic effects of the disaster.
Suggested content for homeowner trainings includes the following:
 Why did your house collapse in the earthquake?
 How likely are more earthquakes in your location?
 How can you make your house resist the next earthquake and other
disasters?
 Design features to avoid and why
 Simple methods for evaluating materials quality
 Concrete mix proportions
 Basics for concrete mixing, masonry work, or other relevant
construction techniques.
Go to http://www.buildchange.org/HousingPrimer.html for examples
of typical instructional materials for homeowners from Indonesia,
China, and Haiti.
3.6. REVIEW AND PAPERWORK FLOW
The drawings and cost estimate are presented to the homeowner for
review. Once the homeowner agrees with the plan, the complete packet
is submitted to the fund distribution implementing partner for first
tranche payment. The homeowner is provided with one set of drawings
for him/herself and one set of drawings to attach to the contract with
the contractor, if used.
All parties involved in the project are responsible for record-keeping:
 The design technical consultant will keep the design file and submit
it to the fund distribution partner when the design is final and ready
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
29
for construction. The design technical consultant will report on how
the number of design packets completed compares to goals.
 The construction technical consultant will keep construction quality
checklists and file for tranche payments. Though construction
management is the responsibility of the contractor/builder, he or she
will keep a daily record of the work performed, the weather
conditions, and other information (for example, safety issues). The
construction technical consultant will also note how the work is
progressing relative to the schedule. An essential element of the
construction technical consultant’s files is a library of photographs
which documents the construction progress and provides adequate
documentation of compliance with construction quality standards.
 The fund distribution implementing partner should keep records
of funds distribution to the homeowners.
 The homeowner should maintain his or her own records, including
the complete design packet with structural, architectural, and detail
drawings, contract with the contractor, receipts for building materials
purchases and payment to contractors.
 The contractor/builder will also maintain his or her own records,
such as contract with the homeowner, drawing packet, daily work log,
reasons for delays, safety issues, receipts for building materials
purchases and payments to builders.
 The USAID project manager must maintain adequate records in
order to be able to readily produce reports on the project’s status,
problems, and successes. He or she will reply primarily on reports
from the technical consultant and fund distribution implementing
partners. It is important that the project manager make routine site
visits and records his/her observations, especially concerning problem
areas. Photographs are important and should be part of the project
manager’s files.
30
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
4. CONTRACTOR/BUILDER
SELECTION
Contractor or builder selection is usually done by the homeowner with
oversight and advice of the technical consultants.
This section covers identification and selection of the contractor or
builder and contracting between the homeowner and builder.
4.1. BUILDER OR CONTRACTOR
IDENTIFICATION
Homeowners can choose to rebuild the house themselves; however, this
choice is usually made only by homeowners who have construction
experience or those who have skilled builders in their family. It is more
common for homeowners to hire a local builder. This is done
individually or as a group; some homeowner-driven reconstruction
projects resemble community-driven reconstruction in that small groups
of homeowners will join together to hire one larger contractor to build
several houses. In this case, the funds may be given to a community
group rather than each individual family.
Builders or builder groups can be selected by the homeowner as follows:
 The homeowner him/herself or relatives
 Local builders selected by the homeowner
 Builders recommended by community leaders
 Builders identified through local trade institutions
Because the homeowner is selecting the builder, it is difficult to
implement a thorough prequalification process. However, the donor or
implementing partner could require some review of the builder’s
experience and/or require the builder’s team to participate in a training
or certification program prior to being considered for a housing
construction contract. Also, providing incentives to promote
construction in compliance with standards, such as the possibility of
winning additional contracts in the future, has proven successful.
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
31
4.2. CONSTRUCTION CONTRACT
Houses built through the informal construction sector in most project
countries rarely have formal contracts in place between the
homeowner/owner and the builder. However, the post-disaster
reconstruction environment provides an opportunity to take this step
forward and implement a simple contract intended to protect the rights
of both the builder and the homeowner.
Relevant government officials should be consulted to determine if such a
contract already exists in practice in the project country. Simple two page
contracts should include the following, as appropriate:
Some Elements of Simple Contracts Between Homeowners and
Contractors
Owner name, address and identification number
Contractor name, address and identification number
Commitment to follow governing law
Project name
Project address
Building footprint area, number of stories
Type of contract (typically lump sum paid in installments)
Total price, specify materials and labor, labor only, materials only; price
usually includes Contractor’s fees, construction management, profit,
taxes
Payment schedule, including defects liability period
Construction schedule (start date, end date, number of days)
Force majeure clause, typically requires homeowner to pay for completed
parts that meet quality specifications; contractor to cover loss of tools or
equipment on site
Homeowner commitment to pay the Contractor per the terms of the
contract
Homeowner’s rights, such as the right to inspect the site and offer
technical inputs
Contractor commitment to complete the construction works to acceptable
quality and on schedule per the terms of the contract, and duty to protect
workers’ safety
Cancellation clause
Signatures of both parties
4.3.
PRE-CONSTRUCTION TRAINING OR
CERTIFICATION
Expectations for quality should be made clear to the contractor. Quality
control is the responsibility of the contractor and the homeowner. For
example, the technical consultant could hold short training courses or
workshops to groups of contractors prior to construction. Homeowners
32
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
and local government officials should be invited to join. These trainings
should cover both construction quality and construction site safety.
4.4. PROJECT SCHEDULE
The schedule is difficult to control in homeowner-driven reconstruction,
as the pace is typically set by the homeowner and contractor.
Interruptions related to weather, holidays, cash flow, and work or family
obligations for the homeowner can be common. However, interruptions
can be minimized if funding is provided promptly as described in the
final section of this Primer.
ANNEXES to Simple Contracts Between
Homeowners and Contractors
Design specifications
Structural, architectural, and construction drawings,
including plan, elevation, relevant sections, standard
connection details
Materials specifications
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
33
5. CONSTRUCTION
SUPERVISION
Construction supervision is necessary to achieve the objective of a
disaster-resistant home, and to authorize the release of the next funding
installment for reconstruction. Construction supervision also provides
an opportunity for on-the-job training of local building professionals.
The level of construction supervision can vary from a cursory review to
a detailed review depending on the complexity of the construction and
the skills of the builders. Construction supervision is best provided by
in-country professionals and technicians, who usually require training
but have been shown to evolve into competent supervisors. The
assigned field personnel’s integrity and attention to detail are very
important. Oversight and mentorship by experienced mid- or seniorlevel professionals is essential.
5.1. CONSTRUCTION CHECKLIST
A simple construction quality checklist should be developed and used in
this process. The level of detail expected in the checklist depends on the
donor’s expectations. Following is a short list of contents in a checklist
used for a typical confined masonry building built in a post-disaster
environment. For a more detailed checklist, please go to
http://www.buildchange.org/HousingPrimer.html.
SAFE SITE and SOIL
Percent slope or slope stability
Setbacks from slopes, riverbeds, drainage, roads, and other
buildings
Soil is not liquefiable sand or expansive clay
MATERIALS QUALITY
Quality of materials, such as sand, gravel, stone, cement,
masonry units, reinforcement, timber, roof covering, others
FOUNDATION
Excavation in correct location and at proper angles, bottom flat
and level, no standing water, loose soil, tree trunks or voids
Soil meets bearing capacity requirements
Foundation base layer meets thickness and strength
34
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
requirements
Foundation follows proper masonry or reinforced concrete
practices (see next sections)
Superstructure elements are anchored in foundation
REINFORCED CONCRETE
Reinforcement diameter, strength, and condition
Reinforcement assembly as per specification
Concrete formwork installed correctly and using spacers to
maintain cover of concrete over steel
Concrete mix proportion as specified
Concrete poured, compacted and cured per specification
MASONRY WALL
Mortar mix proportion as specified
Masonry units laid with proper bonding, staggered joints, joints
completely filled with mortar
Masonry wall cured per specification
Wall is plumb and level
Electrical and plumbing installed properly
Wall plastered and painted per specification
ROOF
Roof tied down to walls
If timber, connections reinforced, roof cover installed to prevent
leakage
If reinforced concrete, follows reinforcement detail specification
and concrete mixing specification
Waterproofing adequate
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
35
6. FUND DISTRIBUTION
Fund distribution takes place at the start of and during the construction
phase. Funds should be distributed in installments, once phases of
construction are complete and deemed to be in compliance with design
specifications and construction quality standards.
Providing funds in installments, contingent upon compliance with
standards, is one of the best ways to increase quality and leverage
reconstruction funding to promote change in construction practices.
Giving funding out in installments at appropriate junctures in construction
is an important mechanism for compelling compliance with building
standards: homeowners should not be provided with the next installment
until compliance has been documented on previous construction steps.
This will help to assure that the work is completed in accordance with the
host country’s understanding and USAID’s regulations and policies. Fund
distribution runs concurrently with the construction phase.
Homeowner-driven housing reconstruction will not produce safe,
complete homes for all if the homeowners do not have sufficient
access to financial resources.
6.1. FUND DISTRIBUTION OPTIONS
Homeowner-driven reconstruction is most effective when the financing
is provided in installments, and contingent upon meeting minimum
standards for design, materials, and construction quality. Some options
for fund distribution include the following:
Provide cash grants to small groups of homeowners
Pros:
 More efficient distribution of cash; fewer transactions and bank
accounts involved
 More economies of scale for labor and building materials: larger scale
contractors could build or retrofit several housing units at once for
small groups of homeowners
 Can use peer pressure to solve problems
36
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
Cons:
 May result in inequitable distribution of funds and/or fees charged by
facilitators
 May result in less individual choice by each homeowner
Provide cash grants to each homeowner
Pros:
 May eliminate “fees” with a facilitator or community group
 Empowers each homeowner to make their own decisions
Cons:
 More administrative requirements, as requires setting up a bank
account for each homeowner
 May be more difficult to solve problems
Provide vouchers for building materials
Pros:
 Higher likelihood that funds are used to purchase building materials
 Allows some control over quality and vendor choice
Cons:
 May encourage nepotism or corruption in the process for selection as
a preferred vendor
 May discourage using small vendors
 Limits choices and provides less empowerment to homeowners.
6.2. FUND DISTRIBUTION SCHEDULE
There are several options, here is one scenario if the donor is providing
all of the funds needed to build a typical confined masonry house:
 Installment 1: Prior to construction. Includes funds needed to
procure sand, gravel, stone, cement, steel, and formwork; and labor to
build the foundation, erect steel for columns and foundation beam,
and pour concrete for the foundation beam.
BUILDING BACK HOUSING IN POST-DISASTER SITUATIONS – BASIC ENGINEERING PRINCIPLES FOR DEVELOPMENT PROFESSIONALS
37
 Installment 2: After completion of foundation. Includes funds
needed to procure masonry units or other wall material, build the wall
and cast the concrete for columns.
 Installment 3: After completion of wall. Includes funds needed to
procure materials for the ring beam and roof and labor to cast the ring
beam and build the roof.
 Installment 4: Finishing bonus, after roof and all structural
elements are completed. Includes funds needed to procure doors,
windows, door and window hardware, flooring, plastering, and
finishing.
If the donor is providing only a portion of the funds needed to build the
house, the homeowner should provide the first installment of funds.
This will help to ensure a complete house is built. Remaining
installments should be proportioned out as above.
38
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
APPENDIX 1:
UNDERSTANDING CAUSES
OF COLLAPSE CONFINED
MASONRY HOUSES IN
INDONESIA
Since the 2004 Indian Ocean tsunami, there have been at least seven earthquakes of significant
strength to cause housing collapses, deaths, and injuries in other parts of Indonesia: Central Java,
M6.3 on May 27, 2006; West Sumatra, M6.4 and 6.3 on March 6, 2007; Bengkulu and the Mentawai
Islands, M8.5, 7.9 and 7.0 on September 12 and 13, 2007, and Padang, West Sumatra M7.6 on September
30, 2009. Strong ground motion recordings are not available for any of the events. The Central Java
event was the most deadly (killing 5,782 people), had the most devastating effect on housing stock,
damaging or destroying 135,000 houses, and yielded compelling examples of good performance of
confined masonry houses in villages where 70-90% of the other buildings were destroyed or heavily
damaged.
Many newly built confined masonry houses with reinforced concrete tie columns and bond beams at the
plinth and roof levels performed well in these earthquakes while confined masonry homes that did not
follow minimum design and construction standards were damaged. See Figures 1 and 2 for a wellbuilt confined masonry house with no evidence of damage, on the edge of heavily damaged Pleret
(2006 Central Java earthquake). In typical confined masonry practice, the tie columns are cast after the
masonry wall was built, flush with the wall, and thus the same width as a brick or block (10 or 11 cm).
Smooth reinforcing steel is common in both Central Java and West Sumatra, typically 6 or 8mm in
diameter with stirrups ranging from 3 to 6mm in diameter. Stirrups were often spaced at 15 to 25 cm
intervals.
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
39
Figure 1 . Well designed and built confined brick
masonry house, edge of heavily damaged Pleret
(Bantul), S7.83686° E110.41552°, IMG_6636
In contrast, the house shown in Figure 3 illustrates
many of the shortcomings common to poorly
designed and built confined masonry houses in
Indonesia – tall slender wall with tendency to
overturn, insufficient connections between
confining elements, no reinforcement in the wall
especially above openings. These flaws, and how
the flaws can be addressed in design, are described
in the following sections. The problems and
solutions are grouped according to the three C’s –
configuration, connections, and construction
quality.
THE FIRST C: CONFIGURATION
Figure 2. Well- built confined masonry wall, house on
edge of heavily damaged Pleret (Bantul), S7.83686°
E110.41552°, IMG_6640
Fig. 3 . Confined masonry house under construction,
insufficient connections, Pleret (Bantul). S7.87574°,
E110.40703°, IMG_6575
(1) MASONRY GABLE WALLS
Problem: Masonry gables are notoriously poor performers in earthquakes (see Figures 4 and 5) and should
be avoided. Damage and failure to masonry gable walls was widespread throughout all three earthquakeaffected regions, and plagued both new and older houses with and without reinforced concrete ring beams.
In most cases, gable masonry was neither properly confined nor properly connected to the roof. Crossbracing between gables was not common.
40
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
Figure 4. Masonry gable wall overturning in 27 May
2006 Central Java Earthquake, Keputren, Pleret
(Bantul) S7.86905° E110.40272°, IMG_6721
Figure 5. Masonry gable wall overturning in 27 May
2006 Central Java Earthquake, (Bantul) S7.89468°,
E110.37341°, IMG_6542
Solution: REMOVE THE MASONRY ABOVE THE RING BEAM: Shift the truss over to rest on the
wall and use a timber or other lightweight cover (Figure 6). Alternatively, use a hipped roof (Figure 7)
which is the lowest cost alternative, and also performs better in high winds.
Figure 6. Papan Gable (Maimunah’s house designed
and built by Build Change, Keunue ue, Peukan Bada,
Aceh Besar)
Figure 7. Rabung Empat Roof (Rusdi Razali’s house
designed and built by Build Change, Keunue ue,
Peukan Bada, Aceh Besar
Other Options: In theory, it should be possible to properly detail and build a masonry gable wall. However,
there are so many construction challenges, including but not limited to: locating the gable beam
reinforcing correctly, bending the reinforcing at the ends at the proper angle, and embedding the
gable beam reinforcement into the columns or ring beams below. Most builders have difficulty
constructing these elements correctly. In Aceh, cases were observed in which the steel cage is assembled,
laid to rest on the wall for show, and just prior to pouring concrete, it is removed and used for the
next house. This results in dangerously insufficient construction.
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
41
(2) LARGE OPENINGS
Problem: Large openings at the front of the house are common. There are many examples from all
earthquakes in which the front of the house has collapsed, while the back of the house remained
intact (see Figures 8 and 9). The problem associated with this lack of stiffness in the in-plane
direction of walls with large openings and lack of confining elements to restrain masonry panels from
failing outwards is exacerbated by the heavy mass of the masonry gable wall.
Figure 8.Collapse of front wall in confined masonry house
, Padang Panjang, IMG_8831
Figure 9. Partially collapsed brick masonry house with
RC tie columns and timber bond beams, note partial
collapse of masonry gable wall, and lack of in-plane
stiffness in front wall, Kec. Lais (North Bengkulu)
S3.53217° E102.03771
Figure 10. Rabung Empat Roof (Rusdi Razali’s house
designed and built by Build Change, Keunue ue,
Peukan Bada, Aceh Besar)
42
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
Solution (Figure 10):
(1) Reduce the weight above the openings by following the previous
recommendation about gable walls,
(2) Reduce the number and area of
windows, and consolidate them to provide longer, continuous shear walls,
(3) Add vertical confining elements to all openings with area greater than
2.5m2. To reduce cost, shift openings from the middle of the panel to the corner, and
(4) Add horizontal reinforcement to the wall every seven courses and above
and below openings.
Other Options: Instead of the horizontal reinforcement every seven courses, consider using a lintel
beam and sill beam.
(3) TALL WALLS and LONG WALLS
Problem: Walls upwards of 4m in height and longer than 6m without crosswalls and bracing are
common and prone to out-of-plane failure, as illustrated in Figure 11 for a tall wall and Figure 12 for a
long wall.
Figure 11. Confined masonry building with overturning
failure of tall, unsupported wall, Kec. Airnapal (North
Bengkulu)
Figure 12. Confined masonry warehouse with
overturning failure of long walls without crossbracing, , IMG 8891
Solution: Reduce the wall height to a maximum of 3m, and add crosswalls or bracing at the ring-beam
level for spans longer than 4m. Tie the walls into the columns using horizontal reinforcement.
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
43
(4) COVERED TERRACES
Problem: Covered terraces are en vogue in Indonesia. These open frame elements often have heavy,
unreinforced and unconfined masonry gable walls above them. The frame elements are poorly detailed
and connected to each other and to the main walls of the house. See Figures 13 and 14.
Figure 13. Subdivision of confined masonry houses,
damage to covered terrace, Bengkulu. S3.83218°
E102.29287
Figure 14.Subdivision of confined masonry houses,
damage to covered terrace, Bengkulu. S3.83218°
E102.29287
Solution: (1) Avoid the covered terrace by using a simple
extended overhang, as shown in Figure 10. Note that this
requires good quality timber, or bracketing to support the
overhang. Or, (2) Reduce the mass above the open frame by
replacing the masonry, and ensure the connections are
detailed properly (Figure 15).
THE SECOND C: CONNECTIONS
(5) BETWEEN CONFINING ELEMENTS
Insufficient connections between reinforced concrete tie
columns and bond beams in confined masonry structures
Figure 15. Covered terrace with lightweight
wall, Build Change designed house for Catholic
contributed to a majority of failures in all three events. The
Relief Services (Aceh Besar)
common practice of terminating the bond beam and tie
column bars in the joint, while providing a small hook at the
end, does not provide sufficient development or confinement. This problem was widespread in all
earthquakes, and a dominant cause of failure for newly-built confined masonry houses in which both tie
columns and bond beams were present. In Indonesia, insufficient connections are a problem that
plagues both confined masonry and RC frame construction. See Figures 16 through 18 for examples.
44
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
Solution: Bend the column reinforcement into the beams and overlap by 50 times the diameter of the
bar. Similarly, bend the plinth and ring beam reinforcing around corners. Tie with double binding wire.
Figure 16. Zoom-in view of ring beam column
connection. IMG_6577
Figure 17. Confined masonry house with
failure in masonry walls and connections
between tie columns and bond beams, Kec.
Airnapal (North Bengkulu)
Figure 18.Connection failure, RC frame
building, Central Java
(6) BETWEEN MASONRY WALL and TIE COLUMN
Problem: Critical to good performance of confined masonry buildings is the connection between the wall
and tie columns. Separation between wall and confining elements occurred in many houses in all
earthquakes. See Figures 19 and 20.
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
45
Figure 19. Insufficient connection between wall
and tie column and between tie column and bond
beam, Pleret (Bantul) S7.88174° E100.40869°,
IMG_6746
Figure 20. Insufficient connection between wall
and tie column and between tie column and bond
beam, Segoroyoso, Pleret (Bantul) S7.88174°
E100.40869°, IMG_6749
Solution: Toothing, which is recommended for confined masonry buildings, is not commonly practiced in
Indonesia. Homeowners and builders are unwilling to spend the extra money and time (respectively) on
additional formwork required to accommodate a toothed wall. Further, our experience has been that it is
difficult to get the concrete to flow completely into the toothed area. Instead, truss-type horizontal steel
reinforcement can be used in the bed joint of the masonry, every seven courses and above and below
openings, and tied into the columns and beams.
(7) BETWEEN RING BEAM and TRUSS
Roof trusses are typically connected to the walls by simply and wrapping the bars from the columns
around the truss chord. Improving this connection can provide some bracing against out-of-plane failure.
Solution: Strengthen this connection by using a U-shaped steel plate with bolts.
THE THIRD C: CONSTRUCTION QUALITY
(8) MASONRY WALL QUALITY AND USE OF PLASTER
The first line of defense in a confined masonry structure in earthquake strong shaking is a well-built
masonry wall. Typical single story confined masonry houses in Indonesia have been shown to perform
well in earthquakes, even when the tie columns are small in section and use smooth bars of small
diameter, provided the masonry wall is well constructed, with adequate bonding between bricks and
mortar. See Figures 21 and 22 for examples of wall collapses with columns and roof intact. Weak
bonding is clearly a contributor to failure (Figure 23); bricks were not soaked in water before building
wall, and/or the mortar mix was too dry.
46
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
Figure 21. Subdivision of confined masonry houses,
collapse of masonry wall exacerbated by insufficient
connections, Bengkulu. S3.83218° E102.29287
Figure 22. Confined masonry house with failure in
masonry walls and connections between tie columns
and bond beams, Kec. Airnapal (North Bengkulu)
Plaster is often ignored in structural engineering analysis; however, for a simple confined masonry
building with a relatively weak wall, high quality cement-based plaster can add significant strength. The
house in Figure 21 is the only house in which wall collapse occurred in a subdivision of similar houses
affected by the 2007 earthquakes near Bengkulu. It is the only house that hadn’t been plastered yet.
Solution: Insist on good construction quality, and finish the wall with cement-based plaster. above it.
Figure 23. Close up view of collapsed ring beam and
wall, same as Fig. 20. Failure plane between top of
mortar bed and bottom of brick above it.
Figure 24. Homeowner standing in front of her
collapsed wall, note quality of concrete, Padang
Panjang, IMG_8840.
(9) CONCRETE QUALITY
Problem: Poor quality concrete also contributed to failures. See Figure 24. Same solutions apply: ensure
good quality materials and workmanship are used.
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
47
(10) FOUNDATION, SOIL and DRAINAGE
Very little earthquake-induced damage to confined masonry houses in Indonesia in recent earthquakes
can be attributed to a soil or foundation problem. In the Central Java event, one example of sliding along
the wall-foundation interface was found; in this case, there was no foundation beam. Effects of
liquefaction were observed in one village in the Bengkulu event (Figure 26).
Figure 25. Displacement alongwall/foundation
interface, Tegal Kebong Agung, Imogir (Bantul)
S7.93434° E110.36667°, CIMG1769
Figure 26. Cracks in foundation and walls associated
with settlement and tilt on liquefiable soils, Lempuing
(Bengkulu), S3.82799° E102.28473
48
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
APPENDIX 2: HOUSING
SUBSECTOR STUDY AND
DESIGN CONFINED
MASONRY HOUSES IN
INDONESIA
HOUSING SUBSECTOR STUDY
In March 2005 we began work in Aceh with a detailed housing subsector study, including a survey of

Common structural systems

Locally available building materials, including quality and cost

Skill level of local builders, and commonly used tools

Architectural and cultural preferences

Climate considerations and other hazards, such as high winds and flooding.
We identified four common structural types (confined masonry, reinforced concrete block masonry,
timber frame on stilts, and timber frame with a masonry skirt), established design criteria, and using
teams of volunteer structural engineers from San Francisco Bay Area design firms, performed
preliminary cost estimating and design analysis on the four systems.1 Funding to build 11 houses in a
pilot project was obtained from Mercy Corps, an international relief and development agency active in
the reconstruction since shortly after the tsunami. We asked each of the 11 homeowners which structural
system they preferred. All chose confined masonry.
The pro bono structural engineers then performed more detailed analysis of a confined masonry house.
At the same time, we hired Acehnese engineers and an architect who created bills of quantity, detailed
drawings, and a suite of floor plans and roofing alternatives that were appropriate to family size, plot size
and local culture.
1
See Hart, T.M. (2006) “Indonesia Tsunami Housing Reconstruction” SEAONC Newsletter, May
2006.
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
49
SEISMIC HAZARD and ANALYSIS METHOD
Building designs were checked for seismic forces in both principal directions using equivalent static
analysis methods. Calculations were performed for a spectral design acceleration of 0.4g.This assumption
is based on
1. Indonesian Seismic Standard (SNI 03-1726-2002) – for Zone 6 on soft soils (0.38g), which is the
highest standard currently applicable in Indonesia. Although the pilot project houses are located
in Zone 5 on medium soil (0.32g), the intent was to design a structural system that could be built
anywhere in Aceh or Nias and assuming the worst case soil condition.
2. International B
International Building Code (IBC) for a building on standard soil and within 2 km of an active
seismic fault that has the potential to generate earthquakes with magnitudes of 5.0 and larger.
The seismic zonation in the most recent version of the Indonesian Seismic Standard (SNI 031726-2002) does not recognize the seismic hazard imposed by the Sumatra fault. Current
research (see Peterson et al.2) indicates that this fault, which lies within a few km of the pilot
project houses, is active and has the potential to produce earthquakes of magnitude 5.0 and
higher.
APPLICABLE CODES AND GUIDELINES
A building code for confined masonry does not yet exist in Indonesia. The Indonesian Seismic Standard
(SNI 03-1726-2002), which is based on UBC 1997, applies to reinforced concrete frame construction.
Infill walls are assumed non-structural and are therefore not addressed in buildings designed according to
the Indonesia Seismic Code. Indonesia has a concrete code, but does not have a masonry code.
The Badan Rehabilitasi dan Rekonstruksi (BRR), the Indonesian governmental agency charged with
overseeing the Aceh recovery program, produced a building guideline for houses in mid-2005.
Given that this guideline was based on the SNI, it was interpreted as applicable to RC frame
construction. The guideline was prescriptive in terms of size of frame elements, diameter of
reinforcing bars, spacing of stirrups and ties, and so on, but it omitted important details such as
connections and anchoring.
During the design process, we reviewed several other codes and guidelines, such as a series of posters
produced by Teddy Boen3, guidance associated with Eurocode 84, Marcial Blondet’s construction
guideline,5 and the IAEE Manual.6 All guidelines were very useful but none was sufficient and
2
Peterson, M.D., Dewey, J. Hartzell, S., Mueller, C., Harmsen, S., Frankel, A.D. and Rukstales, K. “Probablistic seismic hazard
analysis for Sumatra, Indonesia and across the Southern Malaysian Peninsula”, Tectonophysics 390 (2004) 141-158.
3
Boen, Teddy & REKAN (2005). “Syarat-Syarat Minimum Bangunan Tembokan Bata / Batako Tahan
Gempa Dengan Perkuatan Beton Bertulang”
4
5
City University of London http://www.staff.city.ac.uk/earthquakes/MasonryBrick/ConfinedBrickMasonry.htm
Blondet, Marcial (editor).
50
Construction and Maintenance of Masonry Houses: For Masons and
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
completely appropriate for the structural and architectural system common in Aceh.Most codes and
guidelines assume a two or more story structure with rigid diaphragm at the floor level and thicker wall.
In addition to producing our own detailed set of design drawings, bar bending schedules, bills of quality,
we drafted a design and construction guideline for earthquake-resistant confined masonry houses7 which
was shared with BRR and other organizations working in housing at a seminar in May
2006 and through personal communication and meetings with partner organizations. The guideline is
now available on the Build Change website. A simple step-by-step construction guideline for
homeowners and builders is in press.
BRR hired a consultant to check drawings for completeness starting in 2006.
Even though we had
already completed building our pilot project houses, we submitted our drawings for approval in order to
gain additional validation and support for promoting confined masonry with partner organizations.
Approval was granted in late 2006.
Our design for Aceh received a 2006 Excellence in Structural Engineering Award from the Structural
Engineers Association of Northern California and a Certificate of Merit in the statewide competition. An
independent review of one of our designs was done by a structural engineering company in Jakarta. With
the exception of recommending deeper anchorage between the foundation and the foundation beam, the
design was endorsed by the structural engineering firm. Our house design was called “best in Aceh” in
2006 by a team of Indonesian seismic experts. ARUP, an international design engineering firm,
commented in a review of one of our client’s projects, that the Build
Change “design…combines seismic resilience with a high degree of
buildability.”
ARCHITECTURAL, CULTURAL and CLIMATE
CONSIDERATIONS
Single Story. All houses designed and built by Build Change were
single story. Typical two or more story construction in Indonesia is a
hybrid system between RC frame with masonry infill and confined
masonry.
Figure 1. Build Change Pilot
Project House, Hipped Roof
(Owner: Rusdi Razali).
Tall, Slender Wall. Because of the hot climate, there is a preference
for a tall wall, up to 3m in height from floor to ceiling. Masonry is
built using running bond, in which the bricks are laid end to end, resulting in a half-brick wide wall.
This tall, slender wall has an aspect ratio that is higher than what is typically recommended for confined
masonry buildings.
Construction Technicians, PUCP
6
7
IAEE (revised edition, 2004). Guidelines for Earthquake Resistant Non-Engineered Construction.
Build Change (2006) “Earthquake-Resistant Design and Construction Guideline for Single Story Reinforced Concrete
Confined Masonry Houses Built in the Aceh Permanent Housing Reconstruction Program”
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
51
Large Openings. Similarly, there is a preference for tall doors
and windows with vents above over the doors and windows,
especially at the front of the house.
Lightweight, Timber Truss Roof. Pitched or hipped roofs are
preferred because of the significant amount of rainfall.
Other Criteria. The BRR building guideline included additional
architectural criteria which we followed, such as minimum 36m2
in plan, at least two bedrooms, at least two entrances and exits,
orientation appropriate for sun, wind, and Islamic culture, and
toilet, septic tank, soakaway.
DESIGN DETAILS
Foundation and Floor: Trapezoidal-shaped stone masonry strip
footing. S-shaped, 50 cm steel anchors were used every 1m, as
Figure 2. Build Change Pilot Project
recommended by the BRR Guideline. These anchors are intended House, 2 bedroom, 2 living room, toilet
to prevent uplift and to function as shear keys between the stone
outside.
masonry foundation and the plinth beam. The floor was
unreinforced concrete on compacted fill, with finished floor height at least 60 cm above ground surface.
Reinforced Concrete Confining Elements: Reinforced concrete bond beams at the foundation/plinth
and roof level, and reinforced concrete major tie columns at all corners, and wall intersections, minor tie
columns at changes in contour and adjacent to all openings except the small bathroom vent window. See
table 1 for details.
52
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
Table 1. Confining Element Section and Bar Details (dimensions in cm)
BRR Guideline
PLINTH BEAM
--Section
--Longitudinal Bars
--Stirrups
Build Change Design
15 x 20
18 x 25
4-12mm dia smooth 4-10mm dia ribbed
8mm dia at 15 cm
6mm at 15 cm
MAJOR COLUMNS
--Section
15 x 15
15 x 15
--Longitudinal Bars 4-12mm dia smooth 4-10mm dia ribbed
--Ties
8mm dia at 15 cm
6mm at 7.5 cm for the
first 7 ties at top and
bottom, elsewhere
15
cm
MINOR COLUMNS
--Section
11 x 11
11 x 11
--Longitudinal Bars 4-12mm dia smooth 4-8mm dia ribbed
--Ties
8mm dia at 15 cm
6mm at 7.5 cm for the
first 7 ties at top and
bottom, elsewhere
15 cm
RING BEAM
--Section
15 x 20
15 x 20
--Longitudinal Bars 4-12mm dia smooth 4-10mm dia ribbed
We started building our first house with the bar detailing and
section size specified by BRR, however, quickly encountered
construction challenges. We pulled our first foundation beam out
and rebuilt it. How and why we deviated from the BRR Guideline:


Increased the section size of the plinth beam: To
increase the strength of the foundation beam in light
of variable soil conditions, and to make it easier to
connect beams with columns. With a 15 x 20
foundation (plinth) beam and a 15 x 15 column, it is
very difficult to fit column steel inside beam steel,
maintain sufficient cover over the concrete in the
plinth beam, while also maintaining sufficient space
between the long bars in the column, so as to be able
to bend a stirrup that is square, not round.
Figure 3. Bond Beam-Tie Column
Connection Model. Note it has been
suggested that to strengthen the
interior corner, the interior long bars
should pass through the joint and tie
to the external long bars.
Reduced longitudinal bar diameter and used ribbed instead of smooth: 12mm long bars and
8mm bars for stirrups and ties were too difficult for builders to cut and bend properly.
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
53

Reduced the stirrup and tie bar diameter and reduced the spacing of stirrups at the top and
bottom of the columns: again for workability reasons, and to provide increased strength in
shear at the top and bottoms of the columns.

Considered increasing the spacing of stirrups in the bond beams, all of which were resting
on a masonry wall or foundation. Our design calculations indicated that greater stirrup
spacing was allowed.

Specified hook length, hook rotation, and joint detailing on the drawings. It was not
common practice to call out these details on engineering drawings used in Aceh. See Figs. 3
and 4.
Walls: Fired clay brick masonry walls built
prior to casting the columns, with Durowalltype steel reinforcement placed in the bed joint
every seven courses of masonry, above and
below openings, and tied into the columns.
Out of plane failure of the tall, slender wall was
a primary concern in the design process.
Several alternatives were considered in order to
mitigate against out-of-plane failure:
Figure 4. Bond Beam Layout and Connection Detailing
(1) increase the number and length of shear
walls in both directions, and addcross walls or
bracing. All floor plans had cross walls every
4m or less,
(2) increase the wall thickness by changing the masonry bond to English or Flemish bond, as is common
for confined masonry structures in other countries, such as India, Peru, and Iran. To use full-brick wide
bonding, the length of the brick must be twice as long as it’s width plus the thickness of a head joint.
Most of the bricks in Aceh are the wrong proportion for this bonding (too wide and short). Plus, this
type of bond adds cost and requires a higher skill level from the masons, therefore this was not a feasible
option,
(3) reinforce or restrain the wall by using additional confining elements such as extra tie columns, a lintel
beam, or reinforcement in the wall. We considered wrapping wire mesh around the wall, tied into the
foundation and ring beams, but we thought this might be difficult to build, and although the mesh would
be covered in plaster, we had concerns that the mesh would delaminate over time.8 A lintel beam would
add little value at high cost because the top of the frames were already so close to the top of the wall.
8
Inspired by Prof. Ken Elwood, UBC
54
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
We opted for the combined solution of additional vertical
confining elements adjacent to all large openings, and horizontal
steel reinforcement in the wall. The reinforcement detail (Figure
5 and 6) was also assumed to increase the in-plane strength of
the wall. We shifted the openings to the corners to and locations
of major columns so that only one additional tie column would
be needed (rather than two, if the openings remain centered).
All walls were finished
with cement-based
plaster and painted.
Roof. Roof was made
of timber trusses
covered by corrugated
galvanized sheeting.
Figure 5.Horizontal Wall Reinforcement.
Both hipped (Figure 1)
and pitched (Figure 7) roofs covers with CGI sheets were
Figure 6. Wall with Horizontal Reinforcement.
already common. Timber gables were used for pitched roofs.
Trusses were tied down with U-shaped steel plates. The tie
downs were needed to prevent uplift in strong winds, and intended as an alternative the common
practice of wrapping the tie column bars around the trusses, leaving them exposed to corrosion.
Although not considered in the analysis, it is likely that this connection between the roof truss and ring
beam provides some bracing against out of plane failure. The
benefits of having lower mass (and thus lower inertia force) at the roof level by using an already common
and appropriate timber truss roof were considered to outweigh the lack of rigidity at the ring
beam level.
Replacing the roof system with a more rigid system, such as a reinforced concrete slab,
was not considered because such a system is ill-suited to the climate and can be very dangerous if
constructed poorly.
BUILDING MATERIALS AND PROPERTIES
Bricks. Fired clay bricks are widely available in Sumatra.
Soil is mixed by buffalo, machine, or by hand; bricks are handmolded and fired in open kilns using wood or rice husks as fuel.
Brick quality (strength, consistency of size and shape) was variable.
We did a quick review of the brick manufacturing process at several
kilns to determine which vendors to purchase from. The type of clay Figure 7.Build Change Pilot Project House,
Pitched Roof. Owner: Ruslan AB.
and the firing process had the biggest impact on brick quality. Many
brick producers had access only to a source of clay that was prone to warping and shrinking during firing.
The length of burn, fuel used in burning, and the location of the brick in the kiln also strongly influenced
its properties. Bricks at the top of the kiln were rarely completely fired, and would erode or crumble in
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
55
the rain. We used simple three-point bending tests9 (see Figure 8) and
the following checks to evaluate brick strength in the field.

No cracks or chips

No visible unmixed portions or divits

Brick is square, not warped or curved

Dimensions are consistent among a sample of 10-20
bricks; they do not vary by more than 1 cm in the long
direction and 5 mm in width and height

When two bricks are hit together, the sound is a metallic
clink, not a dull thud

When left out in the rain or soaked in water for 24 hours,
bricks do not crumble.
Figure 8. Three point bending test
for brick strength, use average size
Indonesian male, no bouncing
Cement. Two types of cement are common in Sumatra: Type 1 Portland Cement (SNI 15-2049-2004 or
ASTM C-150) and Portland Pozzolan Cement, PPC (SNI 15-0302-2004 or ASTM C-595 M95). We used
Type 1 for the concrete, foundation and floor, and PPC for the masonry wall and plaster, because of the
increased workability and lower price. We have not found lime in local
shops in Indonesia.
Rebar. Both ribbed and smooth bar is available in Aceh. Ribbed bar is
more expensive. We used ribbed bars for longitudinal bars and smooth
for stirrups and ties. SCL performed pro bono tensile tests on 22
random samples of steel reinforcement obtained from local shops,
including both ribbed and smooth steel in diameter between 4 and
13mm. Yield strength was in the range of 57 to 81 ksi for bars in 7 to
13mm diameter range, and 40 ksi was assumed in design.
Durowall-Type Reinforcement. This truss type reinforcement was
initially assembled on-site by the builders using two 6mm diameter bars
tied together with binding wire in a truss pattern (Figure 9, top). This
process was time consuming, and consistent
separation between the long bars was difficult to
Figure 9. Horizontal reinforcement
maintain due to flexibility of the binding wire. We
fabricated on-site with binding wire
(top) and prefabricated at welding shop
switched to a welding school to prefabricate the
(bottom).
reinforcement using 3mm bars as the diagonals
(Figure 9 bottom). When the welding school could
not meet our demand, we used private sector local welding shops.
Figure 10. U-Plate
for ring beam-truss
U-Shaped Steel Plates. The U-shaped steel plates for the ring beam – truss
connection were manufactured by local shops (Figure 10). The 4mm thick, 4cm wide
plates were embedded in the ring beam and bolted to trusses.
56
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
Stone. Angular mountain stone for the stone masonry strip footing was available in yellow, red, and
black varieties. The least expensive yellow stone was a weak, weathered clayey sandstone. We used red,
which is also sandstone, but stronger
connection.
Gravel. Crushed gravel was expensive and not easily found in Aceh. As such, we used rounded gravel
with diameter up to 3 cm. Quality of gravel varied in that depending on the source, some gravel was
coated with fine clay and required rinsing prior to use.
Sand. Like gravel, depending on the source, the sand was often mixed with fine clay particles. To
evaluate sand in the field, we put a handful of sand in a plastic cup or bottle, filled it with water, and
shook it up. If the water was clear, the sand was accepted. If it was cloudy, it was rejected.
Timber. Timber was loosely divided into three classes. Class 1 is tropical hardwood, which was largely
unavailable. Type 2 is a less dense, tropical softwood that is strong enough for structural timber. We used
Class 2 for structural roofing elements and window and door frames. Class 3 includes other softwoods
of lower quality and appropriate only for batterboard and formwork. It was very difficult to reuse
formwork made with such soft, easily warped timber. In later projects, we fabricated formwork out of
plywood that could be used two to three times.
Lightweight Steel. All new houses designed and/or built by Build Change following the 11 pilot project
houses used lightweight steel channels for the roof trusses. This shift away from timber was made due to
the increasing cost and difficulty in obtaining good quality structural timber, and concerns over legality
of the timber source. Although all timber purchased in the pilot project came with documentation
certifying legality, we had concerns about the authenticity of these certificates.
CONSTRUCTION PROCESS
Soils: The pilot project houses were built on coastal alluvium. We screened for soil hazards by
1. inspecting other nearby masonry houses to check for cracks associated with differential
settlement,
2. digging the pits for the septic tanks first so we could take a look at the
soil profile and screen for liquefaction hazards and soft, expansive
clays or peats. Although the water table was within 2-4m of the
ground surface, the soil was clayey, so liquefaction was not considered
a hazard. Expansive clay was a bigger concern. Expansive clays were
identified by touch and shrinkage tests. When it was encountered, we
dug it out and replaced it with compacted fill.
3. (testing the soil strength every 1m along the length of the foundation
excavation by pushing a 12mm diameter steel rod into the ground. If
the rod could be pushed more than 20cm into the ground, we kept
digging.
Stone Masonry Strip Footing Construction: At the base of the excavation,
we used a weak screed layer instead of the more common layer of loose
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
Figure 11. Poorly built
stone masonry strip
footing. Note gaps
between stones, stones
standing on end.
57
cobbles. The challenge with the stone masonry strip footing was to ensure the builders filled all the gaps
between the stones with mortar, laid the stones down rather than standing them up, and used long
stones at corners and t-junctions. See Figure11 for an example of a poorly built strip footing.
Bar Bending and Assembly: In addition to detailed design drawings, we produced bar bending
schedules that showed the cut length of each bar so as to facilitate the overlaps as detailed in the
drawings and reduce waste.
Concrete Mixing and Pouring: Concrete was mixed at 1:2:3 by volume on the ground or on a paved
surface. Builders had a tendency to add too much water to the mix, especially when using a mechanical
mixer on one of our later projects. We used different methods to illustrate the importance of too much
water, from slump tests, and simply picking up a handful of mixed concrete and if the water (and
cement) ran out through one’s fingers, it was too wet.
Concrete spacers were used to separate the steel from the formwork. Concrete spacers were known
about but not common; if the builders used spacers, they used small stones rather than squares of
concrete with binding wire we used in our projects. Formwork was wetted prior to pouring concrete. In
the pilot project, we rammed the concrete with a rod and tapped the formwork with a hammer in order
to compact the concrete. In a later project, we used vibrators, however, the builders had a tendency to
overvibrate and liquefy the concrete. We required builders to cast the entire bond beam all in one day.
Concrete was cured by sprinkling water on it for five to seven days.
During the pilot project, a team of researchers from Institute of Technology – Bandung (ITB)
performed handheld concrete hammer testing on a random sample of concrete elements in our houses.
Foundation beams and column strengths at 28 days or older were in the range of 175-200 kg/cm2,
which meets or exceeds the requirement in the BRR building guideline. According to the researchers,
this was significantly higher than they were finding in houses built by other organizations, which were in
the range of 60-100kg/cm2 at 28 days. One of our ring beams tested at 7 days was 125 kg/cm2.
Figure 12. Typical Build Change
foundation beam, Build Changedesigned house for CRS
Figure 13. Typical Build Change
ring beam, Build Changedesigned house for CRS
Figure 14. Bad practice,
connections and concrete
quality, other organizations
Bricklaying: Mortar was mixed at 1:3 in the same manner as concrete. A mix of 1:2 was used for the
damp proof course and the walls in the bathroom. Because the bricks are so porous, they have a
tendency to absorb water from the mortar before the cement has time to hydrate and create a strong
bond. We promoted wetting or soaking the bricks prior to building the wall.11 In addition, we stressed
uniform joint thickness no greater than 15mm, filling the joints completely with mortar, staggering the
58
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
vertical joints, and ensuring the wall remained plumb. Some examples of masonry produced by Build
Change-trained masons, vs. that produced by other organizations, is shown in Figs. 15 through 20.
Figure 15.Typical wall built by Build
Change-trained mason
Figure 16. Typical wall built by Build
Change-trained mason
Figure 17. Typical wall built by Build
Change-trained mason
Figure 18. Typical wall built by other
mason
Figure 19. Typical wall built by other
mason
Figure 20. Typical wall built by other
mason
Carpentry: Carpentry was the least challenging aspect of the
construction process; we found many skilled carpenters, some of
whom suggested changes to our truss details that made them
simpler to build (Figure 21). The primary challenge with the timber
elements was that some of the window and door frames were
produced with timber that wasn’t totally dry. The frames would
look straight and square when we accepted the order from the
vendor, but a few days in the tropical sun, and some of them would
warp or split.
Figure 21. Builder, homeowner, Build
Change architect, and Build Change
engineer discuss ring beam-truss
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS
59
U.S. Agency for International Development
1300 Pennsylvania Avenue, NW
Washington, DC 20523
Tel: (202) 712-0000
Fax: (202) 216-3524
www.usaid.gov
2
ENGINEERING OF INFRASTRUCTURE PROJECTS FOR DEVELOPMENT PROFESSIONALS